import java.util.*;
public class Binarytree {
    static class TreeNode {
        public char val;
        public TreeNode left;
        public TreeNode right;

        public TreeNode(char val) {
            this.val = val;
        }
    }

    public TreeNode createTree() {
        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        //TreeNode H = new TreeNode('H');

        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        //E.right = H;
        return A;
    }

    public int i = 0;

    public TreeNode createTree(String str) {
        TreeNode root = null;
        if (str.charAt(i) != '#') {
            root = new TreeNode(str.charAt(i));
            i++;
            root.left = createTree(str);
            root.right = createTree(str);
        } else {
            i++;
        }
        return root;
    }

    // 前序遍历
    public void preOrder(TreeNode root) {
        if (root == null) return;
        System.out.print(root.val + " ");
        postOrder(root.left);
        postOrder(root.right);
    }

    // 中序遍历
    void inOrder(TreeNode root) {
        if (root == null) return;

        postOrder(root.left);
        System.out.print(root.val + " ");
        postOrder(root.right);
    }

    // 后序遍历
    void postOrder(TreeNode root) {
        if (root == null) return;

        postOrder(root.left);
        postOrder(root.right);
        System.out.print(root.val + " ");
    }

    // 获取树中节点的个数
    public int size(TreeNode root) {
        if (root == null) return 0;
        return size(root.left) + size(root.right) + 1;
    }

    // 获取叶子节点的个数
    int getLeafNodeCount;

    public int getLeafNodeCount(TreeNode root) {
        if (root == null)
            return 0;
        if (root.left == null && root.right == null) {
            getLeafNodeCount++;
        }
        getLeafNodeCount(root.left);
        getLeafNodeCount(root.right);
        return getLeafNodeCount;
    }

    // 子问题思路-求叶子结点个数
    // 获取第K层节点的个数
    int getGetLeafNodeCount;

    public int getKLevelNodeCount(TreeNode root, int k) {
        if (root == null) {
            return 0;
        }
        if (k == 1) {
            return 1;
        }
        return getKLevelNodeCount(root.left, k - 1) +
                getKLevelNodeCount(root.right, k - 1);
    }

    // 获取二叉树的高度
    int getHeight(TreeNode root) {
        if (root == null) {
            return 0;
        }
        int leftTree = getHeight(root.left);
        int rightTree = getHeight(root.right);
        int max = Math.max(leftTree, rightTree) + 1;
        return max;
    }

    // 检测值为value的元素是否存在
    public TreeNode find(TreeNode root, char val) {
        if (root == null) {
            return null;
        }
        if (root.val == val) {
            return root;
        }
        TreeNode leftT = find(root.left, val);
        if (leftT != null) {
            return leftT;
        }
        TreeNode rightT = find(root.right, val);
        if (rightT != null) {
            return rightT;
        }
        return null;
    }

    //层序遍历
    public void levelOrder(TreeNode root) {
        if (root == null) {
            return;
        }
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);

        while (!queue.isEmpty()) {
            TreeNode cur = queue.poll();
            System.out.print(cur.val + " ");
            if (cur.left != null) {
                queue.offer(cur.left);
            }
            if (cur.right != null) {
                queue.offer(cur.right);
            }
        }
    }

    // 判断一棵树是不是完全二叉树
    boolean isCompleteTree(TreeNode root) {
      /*  if (root == null) {
            return true;
        }
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        while (!queue.isEmpty()) {
            TreeNode cur = queue.poll();
            if (cur != null) {
                queue.offer(root.left);
                queue.offer(root.right);
            } else {
                break;
            }
        }
        while (!queue.isEmpty()) {
            TreeNode peek = queue.peek();
            if (peek != null) {
                return false;
            }
            queue.poll();
        }
        return true;*/

        if(root==null){
                return true;
            }
            Queue<TreeNode> queue=new LinkedList<>();
            queue.offer(root);
            while(!queue.isEmpty()){
                TreeNode cur=queue.poll();
                if(cur.left==null&&cur.right!=null){
                    return false;
                }
                if(cur.left!=null&&cur.right==null){
                    return false;
                }
                if(cur.left!=null){
                    queue.offer(cur.left);
                }
                if (cur.right!=null){
                    queue.offer(cur.right);
                }
            }
            return true;
        }
    }






